Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C55/00—Saturated compounds having more than one carboxyl group bound to acyclic carbon atoms
  • C07C55/32—Saturated compounds having more than one carboxyl group bound to acyclic carbon atoms containing halogen
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/347—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups
  • C07C51/363—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups by introduction of halogen; by substitution of halogen atoms by other halogen atoms

Definitions

• This invention concerns a method of producing the meso-form of 2,3-dibromosuccinic acid.
• 2,3-dibromosuccinic acid can be obtained by the addition of bromine to fumaric or maleic acid, it being possible to form two stereoisomeric forms of which one occurs in two optically active antipodes. While the bromination of fumaric acid gives rise to the optically inactive meso-form of 2,3-dibromosuccinic acid which melts, with decomposition, at a temperature of 260 C., the bromination of maleic acid results in the racemate of the optically active forms of 2,3-dibromosuccinic acid which melts at a temperature of 167 C.
• maleic acid instead of fumaric acid, is subjected to bromination in an aqueous solution, then a mixture of several compounds is likewise produced.
• a method was found of producing the meso-form of 2,3-dibromosuccinic acid by the reaction of fumaric or maleic acid or a mixture thereof with bromine in a molar ratio of 1:1 to 1:1.1 at temperatures of 50 to 90 C. in an aqueous medium.
• the bromine is introduced into a suspension of fumaric or maleic acid or a mixture thereof in an aqueous solution containing 10 to 48% by weight and preferably 20 to 35% by weight dissolved hydrogen bromide.
• the fumaric or maleic acid or a mixture thereof is preferably first suspended in the aqueous solution of hydrogen bromide while this latter is being intensely agitated. It is an ad vantage if the suspension contains, for every part-byweight fumaric or maleic acid or a mixture thereof, 2 to 3 parts-by-weight of the aqueous hydrogen bromide solution. Before commencing to add the bromine, the aqueous hydrogen bromide solution or suspension is heated to a temperature of 50 to 90 C.
• the bromine While the mixture is being stirred vigorously, the bromine is then slowly introduced into the suspension until the reaction mixture contains 1 to 1.1 mole bromine per mole of fumaric or maleic acid. While the bromine is being added, the temperature of the mixture should be kept at 60 to 90 C. The higher the concentration of hydrogen bromide in the hydrogen bromide solution used as the reaction medium, the higher the temperature of the reaction mixture should be within the framework of the range of temperatures indicated. Since bromination of the fumaric or maleic acid is an exothermic reaction, it will in most cases be necessary to cool the reaction mixture during the addition of the bromine. When all the bromine has been added, the reaction mixture should be stirred at the same temperature for some time, about 15 minutes to 2 hours.
• reaction mixture subsequently still exhibit a yellow colouring due to a slight content of free bromine, this colouring can be removed by adding small quantities of water.
• the reaction mixture is then cooled, preferably to temperatures of 10 C. or less.
• the 2,3-dibromosuccinic acid which crystallises as a result is separated from the mother liquor. Any hydrogen bromide which may still be clinging to the 2,3-dibromosuccinic acid can easily be removed by washing, advantageously with water.
• the yield of dry 2,3-dibromosuccinic acid in meso-form which is of adequate purity for most industrial applications, is 90 to 98% of the theoretical value.
• All or part of the residual mother liquor can be used again in the process. Since maleic acid becomes entirely converted to fumaric acid in the presence of hydrobromic acid, it is possible according to the method of the invention, to produce the industrially important meso-form of 2,3-dibromosuccinic acid in high and hitherto unattainable yields not only from fumaric acid but also from maleic acid or from a mixture thereof with fumaric acid on an industrial scale.
• the 2,3-dibromosuccinic acid which has been manufactured according to the invention has been found to have a degree of purity which is entirely adequate for most industrial applications, such as for example as a component in organic synthesis, as a flame-proofing medium or as a biocidal, particularly nematocidal or fungicidal, medium.
• Example 1 6,000 parts-by-weight fumaric acid are stirred into suspension in 15,800 parts-by-weight 20% aqueous hydrobromic acid solution and the mixture brought to a temperature of 54 C. While this suspension is being stirred, 8,400 parts-by-weight bromine are slowly stirred into this suspension. The reaction mixture is maintained, by cooling, at a temperature of to C. When the addition of bromine is completed, the mixture is stirred for about 1 hour at a temperature of 70 C. and then cooled to 10 C. The 2,3-dibromosuccinic acid filtered from the mother liquor is washed with water until no further hydrogen bromide can be traced in the washing water.
• Example 2 11,600 parts-by-weight maleic acid are stirred into suspension into 25,000 parts-by-weight 48% hydrobromic acid at a temperature of 90 C. 16,800 parts-by-weight bromine are slowly stirred into this suspension. The reaction mixture is maintained by cooling at a temperature of 80 C. When the addition of bromine is completed, the mixture is stirred for about 1 hour at a temperature of 70 C. and then cooled to 10 C. The 2,3-dibromosuccinic acid filtered from the mother liquor is washed with water until no more hydrogen bromide can be traced in the washing water.
• the mother liquor remaining is used for the next batch.
• Example 3 5,800 parts-by-weight fumaric acid and 5,800 parts-byweight maleic acid are suspended in 25,000 parts-byweight 48% hydrobromic acid and brominated, as set forth in Example 2, to form 2,3-dibrmosuccinic acid.
• a method of producing the meso-form of 2,3-dibromosuccinic acid which comprises introducing bromine into a suspension of an acid selected from the group consisting of fumaric acid, maleic acid and mixtures thereof in a hot aqueous hydrogen bromide solution containing 10 to 48% by weight HBr while maintaining a temperature between about 50 and 90 C. in said solution, the bromine being introduced into the reaction mixture to provide therein from 1 to 1.1 mole bromine per mole of the acid.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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Cited By (4)

• 1965
  • 1965-02-23 DE DEC35154A patent/DE1232944B/de active Pending
• 1966
  • 1966-01-20 IL IL25021A patent/IL25021A/xx unknown
  • 1966-02-04 GB GB5024/66A patent/GB1078044A/en not_active Expired
  • 1966-02-10 FR FR49175A patent/FR1468014A/fr not_active Expired
  • 1966-02-16 US US527740A patent/US3465037A/en not_active Expired - Lifetime

Non-Patent Citations (1)

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